Studies of the interactions of the opiate-like peptides enkephalins with opiate receptors will be continued. Neurotensin, a peptide with analgesic activities localized to similar brain regions as enkephalin, will be studied in terms of its biosynthesis. Receptor sites for the benzodiazephines will be characterized. The role of bradykinin as a peptide mediating pain perception in the periphery and central nervous system will be examined. The localization of opiate receptors by autoradiography will be explored in newer, greater detail. Mapping of enkephalin neurons and specific pathways will be ascertained. Studies of the development of opiate receptors and effects of specific brain lesions using kainic acid will be pursued.